OWINGS MILLS, Md. (WJZ) — A police trainee shot in the head by his training officer. Now there are new revelations about the moments that led up to the shooting.

A WJZ investigation has uncovered breaches of protocol.

Meghan McCorkell has the latest details.

That training officer has been identified as William Scott Kern, an 18-year veteran of the Baltimore City Police Department.

A Baltimore City police training officer could face criminal charges after a training exercise went terribly wrong. State police are now investigating what happened inside the old Rosewood psychiatric hospital site.

“We will sit back and wait for the investigation to be completed and once that is done we will review it and determine what if any charges will be brought,” said Baltimore County State’s Attorney Scott Shellenberger.

A WJZ investigation has uncovered more than a dozen trainees were at the facility with two Baltimore City training officers.

Sources say after a lunch break, Officer William Scott Kern resumed training without his fellow instructor–a violation of police policy–as both instructors are supposed to check for service weapons during training. Kern mistook his service gun for a training weapon, and fired the shot that hit the trainee, who works for the University of Maryland Baltimore.

WJZ has learned members of the Maryland Police Training Commission were at the city police academy Thursday interviewing staff. The police commissioner has temporarily shut down the academy.

“The commissioner–who is more than just angry–is determined to make sure that we get to the bottom of it to make sure nothing like this ever happens again,” said Mayor Stephanie Rawlings-Blake.

Legal expert Byron Warnken says consequences for Kern will likely be within the department.

“My guess is that their career is in big trouble, maybe even termination. My guess would be it’s not going to be criminal,” he said.

The state still owns Rosewood. Baltimore County Police have used it to train for years, but this is the first time it has been used by the city.

State police say the investigation could take weeks, telling WJZ:

“Investigators are continuing to conduct interviews with persons who were at the shooting scene. The investigation is being conducted as a criminal investigation with the purpose of determining if a crime occurred [and is] not an administrative investigation. An administrative investigation examines the adherence of personnel to department policies.”